Conventional rotary fluid devices are used for a variety of purposes such as to transfer fluid (i.e., water, oil, etc.) from one location to another (e.g., a pump) or to convert fluid pressure into torque (e.g., a motor). Most conventional rotary fluid devices include a rotor. The rotor cooperates with other components of the conventional rotary fluid device to achieve its pumping or motoring purpose.
In conventional rotary fluid devices, the rotor is typically an all-metal design. However, during normal operation, localized welding and splitting (“galling”) can occur between the rotor and the immediately adjacent component as a result of friction between the rotor and the immediately adjacent component. This localized welding and splitting can significantly reduce the life of the conventional rotary fluid device.